//     Underscore.js 1.9.1
//     http://underscorejs.org
//     (c) 2009-2018 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
//     Underscore may be freely distributed under the MIT license.

(function() {

    // Baseline setup
    // --------------
  
    // Establish the root object, `window` (`self`) in the browser, `global`
    // on the server, or `this` in some virtual machines. We use `self`
    // instead of `window` for `WebWorker` support.
    var root = typeof self == 'object' && self.self === self && self ||
              typeof global == 'object' && global.global === global && global ||
              this ||
              {};
  
    // Save the previous value of the `_` variable.
    var previousUnderscore = root._;
  
    // Save bytes in the minified (but not gzipped) version:
    var ArrayProto = Array.prototype, ObjProto = Object.prototype;
    var SymbolProto = typeof Symbol !== 'undefined' ? Symbol.prototype : null;
  
    // Create quick reference variables for speed access to core prototypes.
    var push = ArrayProto.push,
        slice = ArrayProto.slice,
        toString = ObjProto.toString,
        hasOwnProperty = ObjProto.hasOwnProperty;
  
    // All **ECMAScript 5** native function implementations that we hope to use
    // are declared here.
    var nativeIsArray = Array.isArray,
        nativeKeys = Object.keys,
        nativeCreate = Object.create;
  
    // Naked function reference for surrogate-prototype-swapping.
    var Ctor = function(){};
  
    // Create a safe reference to the Underscore object for use below.
    var _ = function(obj) {
      if (obj instanceof _) return obj;
      if (!(this instanceof _)) return new _(obj);
      this._wrapped = obj;
    };
  
    // Export the Underscore object for **Node.js**, with
    // backwards-compatibility for their old module API. If we're in
    // the browser, add `_` as a global object.
    // (`nodeType` is checked to ensure that `module`
    // and `exports` are not HTML elements.)
    // console.log(exports.nodeType)
    // if (typeof exports != 'undefined' && !exports.nodeType) {
    //   if (typeof module != 'undefined' && !module.nodeType && module.exports) {
    //     exports = module.exports = _;
    //   }
    //   exports._ = _;
    // } else {
    //   console.log('dd')
    //   root._ = _;
    // }
    root._ = _;
    // Current version.
    // _.VERSION = '1.9.1';
  
    // Internal function that returns an efficient (for current engines) version
    // of the passed-in callback, to be repeatedly applied in other Underscore
    // functions.
    // var optimizeCb = function(func, context, argCount) {
    //   if (context === void 0) return func;
    //   switch (argCount == null ? 3 : argCount) {
    //     case 1: return function(value) {
    //       return func.call(context, value);
    //     };
    //     // The 2-argument case is omitted because we’re not using it.
    //     case 3: return function(value, index, collection) {
    //       return func.call(context, value, index, collection);
    //     };
    //     case 4: return function(accumulator, value, index, collection) {
    //       return func.call(context, accumulator, value, index, collection);
    //     };
    //   }
    //   return function() {
    //     return func.apply(context, arguments);
    //   };
    // };
  
    // var builtinIteratee;
  
    // An internal function to generate callbacks that can be applied to each
    // element in a collection, returning the desired result — either `identity`,
    // an arbitrary callback, a property matcher, or a property accessor.
    // var cb = function(value, context, argCount) {
    //   if (_.iteratee !== builtinIteratee) return _.iteratee(value, context);
    //   if (value == null) return _.identity;
    //   if (_.isFunction(value)) return optimizeCb(value, context, argCount);
    //   if (_.isObject(value) && !_.isArray(value)) return _.matcher(value);
    //   return _.property(value);
    // };
  
    // // External wrapper for our callback generator. Users may customize
    // // `_.iteratee` if they want additional predicate/iteratee shorthand styles.
    // // This abstraction hides the internal-only argCount argument.
    // _.iteratee = builtinIteratee = function(value, context) {
    //   return cb(value, context, Infinity);
    // };
  
    // // Some functions take a variable number of arguments, or a few expected
    // // arguments at the beginning and then a variable number of values to operate
    // // on. This helper accumulates all remaining arguments past the function’s
    // // argument length (or an explicit `startIndex`), into an array that becomes
    // // the last argument. Similar to ES6’s "rest parameter".
    // var restArguments = function(func, startIndex) {
    //   startIndex = startIndex == null ? func.length - 1 : +startIndex;
    //   return function() {
    //     var length = Math.max(arguments.length - startIndex, 0),
    //         rest = Array(length),
    //         index = 0;
    //     for (; index < length; index++) {
    //       rest[index] = arguments[index + startIndex];
    //     }
    //     switch (startIndex) {
    //       case 0: return func.call(this, rest);
    //       case 1: return func.call(this, arguments[0], rest);
    //       case 2: return func.call(this, arguments[0], arguments[1], rest);
    //     }
    //     var args = Array(startIndex + 1);
    //     for (index = 0; index < startIndex; index++) {
    //       args[index] = arguments[index];
    //     }
    //     args[startIndex] = rest;
    //     return func.apply(this, args);
    //   };
    // };
  
    // // An internal function for creating a new object that inherits from another.
    // var baseCreate = function(prototype) {
    //   if (!_.isObject(prototype)) return {};
    //   if (nativeCreate) return nativeCreate(prototype);
    //   Ctor.prototype = prototype;
    //   var result = new Ctor;
    //   Ctor.prototype = null;
    //   return result;
    // };
  
    // var shallowProperty = function(key) {
    //   return function(obj) {
    //     return obj == null ? void 0 : obj[key];
    //   };
    // };
  
    // var has = function(obj, path) {
    //   return obj != null && hasOwnProperty.call(obj, path);
    // }
  
    // var deepGet = function(obj, path) {
    //   var length = path.length;
    //   for (var i = 0; i < length; i++) {
    //     if (obj == null) return void 0;
    //     obj = obj[path[i]];
    //   }
    //   return length ? obj : void 0;
    // };
  
    // // Helper for collection methods to determine whether a collection
    // // should be iterated as an array or as an object.
    // // Related: http://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength
    // // Avoids a very nasty iOS 8 JIT bug on ARM-64. #2094
    // var MAX_ARRAY_INDEX = Math.pow(2, 53) - 1;
    // var getLength = shallowProperty('length');
    // var isArrayLike = function(collection) {
    //   var length = getLength(collection);
    //   return typeof length == 'number' && length >= 0 && length <= MAX_ARRAY_INDEX;
    // };
  
    // // Collection Functions
    // // --------------------
  
    // // The cornerstone, an `each` implementation, aka `forEach`.
    // // Handles raw objects in addition to array-likes. Treats all
    // // sparse array-likes as if they were dense.
    // _.each = _.forEach = function(obj, iteratee, context) {
    //   iteratee = optimizeCb(iteratee, context);
    //   var i, length;
    //   if (isArrayLike(obj)) {
    //     for (i = 0, length = obj.length; i < length; i++) {
    //       iteratee(obj[i], i, obj);
    //     }
    //   } else {
    //     var keys = _.keys(obj);
    //     for (i = 0, length = keys.length; i < length; i++) {
    //       iteratee(obj[keys[i]], keys[i], obj);
    //     }
    //   }
    //   return obj;
    // };
  
    // // Return the results of applying the iteratee to each element.
    // _.map = _.collect = function(obj, iteratee, context) {
    //   iteratee = cb(iteratee, context);
    //   var keys = !isArrayLike(obj) && _.keys(obj),
    //       length = (keys || obj).length,
    //       results = Array(length);
    //   for (var index = 0; index < length; index++) {
    //     var currentKey = keys ? keys[index] : index;
    //     results[index] = iteratee(obj[currentKey], currentKey, obj);
    //   }
    //   return results;
    // };
  
    // // Create a reducing function iterating left or right.
    // var createReduce = function(dir) {
    //   // Wrap code that reassigns argument variables in a separate function than
    //   // the one that accesses `arguments.length` to avoid a perf hit. (#1991)
    //   var reducer = function(obj, iteratee, memo, initial) {
    //     var keys = !isArrayLike(obj) && _.keys(obj),
    //         length = (keys || obj).length,
    //         index = dir > 0 ? 0 : length - 1;
    //     if (!initial) {
    //       memo = obj[keys ? keys[index] : index];
    //       index += dir;
    //     }
    //     for (; index >= 0 && index < length; index += dir) {
    //       var currentKey = keys ? keys[index] : index;
    //       memo = iteratee(memo, obj[currentKey], currentKey, obj);
    //     }
    //     return memo;
    //   };
  
    //   return function(obj, iteratee, memo, context) {
    //     var initial = arguments.length >= 3;
    //     return reducer(obj, optimizeCb(iteratee, context, 4), memo, initial);
    //   };
    // };
  
    // // **Reduce** builds up a single result from a list of values, aka `inject`,
    // // or `foldl`.
    // _.reduce = _.foldl = _.inject = createReduce(1);
  
    // // The right-associative version of reduce, also known as `foldr`.
    // _.reduceRight = _.foldr = createReduce(-1);
  
    // // Return the first value which passes a truth test. Aliased as `detect`.
    // _.find = _.detect = function(obj, predicate, context) {
    //   var keyFinder = isArrayLike(obj) ? _.findIndex : _.findKey;
    //   var key = keyFinder(obj, predicate, context);
    //   if (key !== void 0 && key !== -1) return obj[key];
    // };
  
    // // Return all the elements that pass a truth test.
    // // Aliased as `select`.
    // _.filter = _.select = function(obj, predicate, context) {
    //   var results = [];
    //   predicate = cb(predicate, context);
    //   _.each(obj, function(value, index, list) {
    //     if (predicate(value, index, list)) results.push(value);
    //   });
    //   return results;
    // };
  
    // // Return all the elements for which a truth test fails.
    // _.reject = function(obj, predicate, context) {
    //   return _.filter(obj, _.negate(cb(predicate)), context);
    // };
  
    // // Determine whether all of the elements match a truth test.
    // // Aliased as `all`.
    // _.every = _.all = function(obj, predicate, context) {
    //   predicate = cb(predicate, context);
    //   var keys = !isArrayLike(obj) && _.keys(obj),
    //       length = (keys || obj).length;
    //   for (var index = 0; index < length; index++) {
    //     var currentKey = keys ? keys[index] : index;
    //     if (!predicate(obj[currentKey], currentKey, obj)) return false;
    //   }
    //   return true;
    // };
  
    // // Determine if at least one element in the object matches a truth test.
    // // Aliased as `any`.
    // _.some = _.any = function(obj, predicate, context) {
    //   predicate = cb(predicate, context);
    //   var keys = !isArrayLike(obj) && _.keys(obj),
    //       length = (keys || obj).length;
    //   for (var index = 0; index < length; index++) {
    //     var currentKey = keys ? keys[index] : index;
    //     if (predicate(obj[currentKey], currentKey, obj)) return true;
    //   }
    //   return false;
    // };
  
    // // Determine if the array or object contains a given item (using `===`).
    // // Aliased as `includes` and `include`.
    // _.contains = _.includes = _.include = function(obj, item, fromIndex, guard) {
    //   if (!isArrayLike(obj)) obj = _.values(obj);
    //   if (typeof fromIndex != 'number' || guard) fromIndex = 0;
    //   return _.indexOf(obj, item, fromIndex) >= 0;
    // };
  
    // // Invoke a method (with arguments) on every item in a collection.
    // _.invoke = restArguments(function(obj, path, args) {
    //   var contextPath, func;
    //   if (_.isFunction(path)) {
    //     func = path;
    //   } else if (_.isArray(path)) {
    //     contextPath = path.slice(0, -1);
    //     path = path[path.length - 1];
    //   }
    //   return _.map(obj, function(context) {
    //     var method = func;
    //     if (!method) {
    //       if (contextPath && contextPath.length) {
    //         context = deepGet(context, contextPath);
    //       }
    //       if (context == null) return void 0;
    //       method = context[path];
    //     }
    //     return method == null ? method : method.apply(context, args);
    //   });
    // });
  
    // // Convenience version of a common use case of `map`: fetching a property.
    // _.pluck = function(obj, key) {
    //   return _.map(obj, _.property(key));
    // };
  
    // // Convenience version of a common use case of `filter`: selecting only objects
    // // containing specific `key:value` pairs.
    // _.where = function(obj, attrs) {
    //   return _.filter(obj, _.matcher(attrs));
    // };
  
    // // Convenience version of a common use case of `find`: getting the first object
    // // containing specific `key:value` pairs.
    // _.findWhere = function(obj, attrs) {
    //   return _.find(obj, _.matcher(attrs));
    // };
  
    // // Return the maximum element (or element-based computation).
    // _.max = function(obj, iteratee, context) {
    //   var result = -Infinity, lastComputed = -Infinity,
    //       value, computed;
    //   if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
    //     obj = isArrayLike(obj) ? obj : _.values(obj);
    //     for (var i = 0, length = obj.length; i < length; i++) {
    //       value = obj[i];
    //       if (value != null && value > result) {
    //         result = value;
    //       }
    //     }
    //   } else {
    //     iteratee = cb(iteratee, context);
    //     _.each(obj, function(v, index, list) {
    //       computed = iteratee(v, index, list);
    //       if (computed > lastComputed || computed === -Infinity && result === -Infinity) {
    //         result = v;
    //         lastComputed = computed;
    //       }
    //     });
    //   }
    //   return result;
    // };
  
    // // Return the minimum element (or element-based computation).
    // _.min = function(obj, iteratee, context) {
    //   var result = Infinity, lastComputed = Infinity,
    //       value, computed;
    //   if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
    //     obj = isArrayLike(obj) ? obj : _.values(obj);
    //     for (var i = 0, length = obj.length; i < length; i++) {
    //       value = obj[i];
    //       if (value != null && value < result) {
    //         result = value;
    //       }
    //     }
    //   } else {
    //     iteratee = cb(iteratee, context);
    //     _.each(obj, function(v, index, list) {
    //       computed = iteratee(v, index, list);
    //       if (computed < lastComputed || computed === Infinity && result === Infinity) {
    //         result = v;
    //         lastComputed = computed;
    //       }
    //     });
    //   }
    //   return result;
    // };
  
    // // Shuffle a collection.
    // _.shuffle = function(obj) {
    //   return _.sample(obj, Infinity);
    // };
  
    // Sample **n** random values from a collection using the modern version of the
    // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/Fisher–Yates_shuffle).
    // If **n** is not specified, returns a single random element.
    // The internal `guard` argument allows it to work with `map`.
    // _.sample = function(obj, n, guard) {
    //   if (n == null || guard) {
    //     if (!isArrayLike(obj)) obj = _.values(obj);
    //     return obj[_.random(obj.length - 1)];
    //   }
    //   var sample = isArrayLike(obj) ? _.clone(obj) : _.values(obj);
    //   var length = getLength(sample);
    //   n = Math.max(Math.min(n, length), 0);
    //   var last = length - 1;
    //   for (var index = 0; index < n; index++) {
    //     var rand = _.random(index, last);
    //     var temp = sample[index];
    //     sample[index] = sample[rand];
    //     sample[rand] = temp;
    //   }
    //   return sample.slice(0, n);
    // };
  
    // // Sort the object's values by a criterion produced by an iteratee.
    // _.sortBy = function(obj, iteratee, context) {
    //   var index = 0;
    //   iteratee = cb(iteratee, context);
    //   return _.pluck(_.map(obj, function(value, key, list) {
    //     return {
    //       value: value,
    //       index: index++,
    //       criteria: iteratee(value, key, list)
    //     };
    //   }).sort(function(left, right) {
    //     var a = left.criteria;
    //     var b = right.criteria;
    //     if (a !== b) {
    //       if (a > b || a === void 0) return 1;
    //       if (a < b || b === void 0) return -1;
    //     }
    //     return left.index - right.index;
    //   }), 'value');
    // };
  
    // // An internal function used for aggregate "group by" operations.
    // var group = function(behavior, partition) {
    //   return function(obj, iteratee, context) {
    //     var result = partition ? [[], []] : {};
    //     iteratee = cb(iteratee, context);
    //     _.each(obj, function(value, index) {
    //       var key = iteratee(value, index, obj);
    //       behavior(result, value, key);
    //     });
    //     return result;
    //   };
    // };
  
    // // Groups the object's values by a criterion. Pass either a string attribute
    // // to group by, or a function that returns the criterion.
    // _.groupBy = group(function(result, value, key) {
    //   if (has(result, key)) result[key].push(value); else result[key] = [value];
    // });
  
    // // Indexes the object's values by a criterion, similar to `groupBy`, but for
    // // when you know that your index values will be unique.
    // _.indexBy = group(function(result, value, key) {
    //   result[key] = value;
    // });
  
    // // Counts instances of an object that group by a certain criterion. Pass
    // // either a string attribute to count by, or a function that returns the
    // // criterion.
    // _.countBy = group(function(result, value, key) {
    //   if (has(result, key)) result[key]++; else result[key] = 1;
    // });
  
    // var reStrSymbol = /[^\ud800-\udfff]|[\ud800-\udbff][\udc00-\udfff]|[\ud800-\udfff]/g;
    // // Safely create a real, live array from anything iterable.
    // _.toArray = function(obj) {
    //   if (!obj) return [];
    //   if (_.isArray(obj)) return slice.call(obj);
    //   if (_.isString(obj)) {
    //     // Keep surrogate pair characters together
    //     return obj.match(reStrSymbol);
    //   }
    //   if (isArrayLike(obj)) return _.map(obj, _.identity);
    //   return _.values(obj);
    // };
  
    // // Return the number of elements in an object.
    // _.size = function(obj) {
    //   if (obj == null) return 0;
    //   return isArrayLike(obj) ? obj.length : _.keys(obj).length;
    // };
  
    // // Split a collection into two arrays: one whose elements all satisfy the given
    // // predicate, and one whose elements all do not satisfy the predicate.
    // _.partition = group(function(result, value, pass) {
    //   result[pass ? 0 : 1].push(value);
    // }, true);
  
    // // Array Functions
    // // ---------------
  
    // // Get the first element of an array. Passing **n** will return the first N
    // // values in the array. Aliased as `head` and `take`. The **guard** check
    // // allows it to work with `_.map`.
    // _.first = _.head = _.take = function(array, n, guard) {
    //   if (array == null || array.length < 1) return n == null ? void 0 : [];
    //   if (n == null || guard) return array[0];
    //   return _.initial(array, array.length - n);
    // };
  
    // // Returns everything but the last entry of the array. Especially useful on
    // // the arguments object. Passing **n** will return all the values in
    // // the array, excluding the last N.
    // _.initial = function(array, n, guard) {
    //   return slice.call(array, 0, Math.max(0, array.length - (n == null || guard ? 1 : n)));
    // };
  
    // // Get the last element of an array. Passing **n** will return the last N
    // // values in the array.
    // _.last = function(array, n, guard) {
    //   if (array == null || array.length < 1) return n == null ? void 0 : [];
    //   if (n == null || guard) return array[array.length - 1];
    //   return _.rest(array, Math.max(0, array.length - n));
    // };
  
    // // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
    // // Especially useful on the arguments object. Passing an **n** will return
    // // the rest N values in the array.
    // _.rest = _.tail = _.drop = function(array, n, guard) {
    //   return slice.call(array, n == null || guard ? 1 : n);
    // };
  
    // // Trim out all falsy values from an array.
    // _.compact = function(array) {
    //   return _.filter(array, Boolean);
    // };
  
    // // Internal implementation of a recursive `flatten` function.
    // var flatten = function(input, shallow, strict, output) {
    //   output = output || [];
    //   var idx = output.length;
    //   for (var i = 0, length = getLength(input); i < length; i++) {
    //     var value = input[i];
    //     if (isArrayLike(value) && (_.isArray(value) || _.isArguments(value))) {
    //       // Flatten current level of array or arguments object.
    //       if (shallow) {
    //         var j = 0, len = value.length;
    //         while (j < len) output[idx++] = value[j++];
    //       } else {
    //         flatten(value, shallow, strict, output);
    //         idx = output.length;
    //       }
    //     } else if (!strict) {
    //       output[idx++] = value;
    //     }
    //   }
    //   return output;
    // };
  
    // // Flatten out an array, either recursively (by default), or just one level.
    // _.flatten = function(array, shallow) {
    //   return flatten(array, shallow, false);
    // };
  
    // // Return a version of the array that does not contain the specified value(s).
    // _.without = restArguments(function(array, otherArrays) {
    //   return _.difference(array, otherArrays);
    // });
  
    // // Produce a duplicate-free version of the array. If the array has already
    // // been sorted, you have the option of using a faster algorithm.
    // // The faster algorithm will not work with an iteratee if the iteratee
    // // is not a one-to-one function, so providing an iteratee will disable
    // // the faster algorithm.
    // // Aliased as `unique`.
    // _.uniq = _.unique = function(array, isSorted, iteratee, context) {
    //   if (!_.isBoolean(isSorted)) {
    //     context = iteratee;
    //     iteratee = isSorted;
    //     isSorted = false;
    //   }
    //   if (iteratee != null) iteratee = cb(iteratee, context);
    //   var result = [];
    //   var seen = [];
    //   for (var i = 0, length = getLength(array); i < length; i++) {
    //     var value = array[i],
    //         computed = iteratee ? iteratee(value, i, array) : value;
    //     if (isSorted && !iteratee) {
    //       if (!i || seen !== computed) result.push(value);
    //       seen = computed;
    //     } else if (iteratee) {
    //       if (!_.contains(seen, computed)) {
    //         seen.push(computed);
    //         result.push(value);
    //       }
    //     } else if (!_.contains(result, value)) {
    //       result.push(value);
    //     }
    //   }
    //   return result;
    // };
  
    // // Produce an array that contains the union: each distinct element from all of
    // // the passed-in arrays.
    // _.union = restArguments(function(arrays) {
    //   return _.uniq(flatten(arrays, true, true));
    // });
  
    // // Produce an array that contains every item shared between all the
    // // passed-in arrays.
    // _.intersection = function(array) {
    //   var result = [];
    //   var argsLength = arguments.length;
    //   for (var i = 0, length = getLength(array); i < length; i++) {
    //     var item = array[i];
    //     if (_.contains(result, item)) continue;
    //     var j;
    //     for (j = 1; j < argsLength; j++) {
    //       if (!_.contains(arguments[j], item)) break;
    //     }
    //     if (j === argsLength) result.push(item);
    //   }
    //   return result;
    // };
  
    // // Take the difference between one array and a number of other arrays.
    // // Only the elements present in just the first array will remain.
    // _.difference = restArguments(function(array, rest) {
    //   rest = flatten(rest, true, true);
    //   return _.filter(array, function(value){
    //     return !_.contains(rest, value);
    //   });
    // });
  
    // // Complement of _.zip. Unzip accepts an array of arrays and groups
    // // each array's elements on shared indices.
    // _.unzip = function(array) {
    //   var length = array && _.max(array, getLength).length || 0;
    //   var result = Array(length);
  
    //   for (var index = 0; index < length; index++) {
    //     result[index] = _.pluck(array, index);
    //   }
    //   return result;
    // };
  
    // // Zip together multiple lists into a single array -- elements that share
    // // an index go together.
    // _.zip = restArguments(_.unzip);
  
    // // Converts lists into objects. Pass either a single array of `[key, value]`
    // // pairs, or two parallel arrays of the same length -- one of keys, and one of
    // // the corresponding values. Passing by pairs is the reverse of _.pairs.
    // _.object = function(list, values) {
    //   var result = {};
    //   for (var i = 0, length = getLength(list); i < length; i++) {
    //     if (values) {
    //       result[list[i]] = values[i];
    //     } else {
    //       result[list[i][0]] = list[i][1];
    //     }
    //   }
    //   return result;
    // };
  
    // // Generator function to create the findIndex and findLastIndex functions.
    // var createPredicateIndexFinder = function(dir) {
    //   return function(array, predicate, context) {
    //     predicate = cb(predicate, context);
    //     var length = getLength(array);
    //     var index = dir > 0 ? 0 : length - 1;
    //     for (; index >= 0 && index < length; index += dir) {
    //       if (predicate(array[index], index, array)) return index;
    //     }
    //     return -1;
    //   };
    // };
  
    // // Returns the first index on an array-like that passes a predicate test.
    // _.findIndex = createPredicateIndexFinder(1);
    // _.findLastIndex = createPredicateIndexFinder(-1);
  
    // // Use a comparator function to figure out the smallest index at which
    // // an object should be inserted so as to maintain order. Uses binary search.
    // _.sortedIndex = function(array, obj, iteratee, context) {
    //   iteratee = cb(iteratee, context, 1);
    //   var value = iteratee(obj);
    //   var low = 0, high = getLength(array);
    //   while (low < high) {
    //     var mid = Math.floor((low + high) / 2);
    //     if (iteratee(array[mid]) < value) low = mid + 1; else high = mid;
    //   }
    //   return low;
    // };
  
    // // Generator function to create the indexOf and lastIndexOf functions.
    // var createIndexFinder = function(dir, predicateFind, sortedIndex) {
    //   return function(array, item, idx) {
    //     var i = 0, length = getLength(array);
    //     if (typeof idx == 'number') {
    //       if (dir > 0) {
    //         i = idx >= 0 ? idx : Math.max(idx + length, i);
    //       } else {
    //         length = idx >= 0 ? Math.min(idx + 1, length) : idx + length + 1;
    //       }
    //     } else if (sortedIndex && idx && length) {
    //       idx = sortedIndex(array, item);
    //       return array[idx] === item ? idx : -1;
    //     }
    //     if (item !== item) {
    //       idx = predicateFind(slice.call(array, i, length), _.isNaN);
    //       return idx >= 0 ? idx + i : -1;
    //     }
    //     for (idx = dir > 0 ? i : length - 1; idx >= 0 && idx < length; idx += dir) {
    //       if (array[idx] === item) return idx;
    //     }
    //     return -1;
    //   };
    // };
  
    // // Return the position of the first occurrence of an item in an array,
    // // or -1 if the item is not included in the array.
    // // If the array is large and already in sort order, pass `true`
    // // for **isSorted** to use binary search.
    // _.indexOf = createIndexFinder(1, _.findIndex, _.sortedIndex);
    // _.lastIndexOf = createIndexFinder(-1, _.findLastIndex);
  
    // // Generate an integer Array containing an arithmetic progression. A port of
    // // the native Python `range()` function. See
    // // [the Python documentation](http://docs.python.org/library/functions.html#range).
    // _.range = function(start, stop, step) {
    //   if (stop == null) {
    //     stop = start || 0;
    //     start = 0;
    //   }
    //   if (!step) {
    //     step = stop < start ? -1 : 1;
    //   }
  
    //   var length = Math.max(Math.ceil((stop - start) / step), 0);
    //   var range = Array(length);
  
    //   for (var idx = 0; idx < length; idx++, start += step) {
    //     range[idx] = start;
    //   }
  
    //   return range;
    // };
  
    // // Chunk a single array into multiple arrays, each containing `count` or fewer
    // // items.
    // _.chunk = function(array, count) {
    //   if (count == null || count < 1) return [];
    //   var result = [];
    //   var i = 0, length = array.length;
    //   while (i < length) {
    //     result.push(slice.call(array, i, i += count));
    //   }
    //   return result;
    // };
  
    // // Function (ahem) Functions
    // // ------------------
  
    // // Determines whether to execute a function as a constructor
    // // or a normal function with the provided arguments.
    // var executeBound = function(sourceFunc, boundFunc, context, callingContext, args) {
    //   if (!(callingContext instanceof boundFunc)) return sourceFunc.apply(context, args);
    //   var self = baseCreate(sourceFunc.prototype);
    //   var result = sourceFunc.apply(self, args);
    //   if (_.isObject(result)) return result;
    //   return self;
    // };
  
    // // Create a function bound to a given object (assigning `this`, and arguments,
    // // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
    // // available.
    // _.bind = restArguments(function(func, context, args) {
    //   if (!_.isFunction(func)) throw new TypeError('Bind must be called on a function');
    //   var bound = restArguments(function(callArgs) {
    //     return executeBound(func, bound, context, this, args.concat(callArgs));
    //   });
    //   return bound;
    // });
  
    // // Partially apply a function by creating a version that has had some of its
    // // arguments pre-filled, without changing its dynamic `this` context. _ acts
    // // as a placeholder by default, allowing any combination of arguments to be
    // // pre-filled. Set `_.partial.placeholder` for a custom placeholder argument.
    // _.partial = restArguments(function(func, boundArgs) {
    //   var placeholder = _.partial.placeholder;
    //   var bound = function() {
    //     var position = 0, length = boundArgs.length;
    //     var args = Array(length);
    //     for (var i = 0; i < length; i++) {
    //       args[i] = boundArgs[i] === placeholder ? arguments[position++] : boundArgs[i];
    //     }
    //     while (position < arguments.length) args.push(arguments[position++]);
    //     return executeBound(func, bound, this, this, args);
    //   };
    //   return bound;
    // });
  
    // _.partial.placeholder = _;
  
    // // Bind a number of an object's methods to that object. Remaining arguments
    // // are the method names to be bound. Useful for ensuring that all callbacks
    // // defined on an object belong to it.
    // _.bindAll = restArguments(function(obj, keys) {
    //   keys = flatten(keys, false, false);
    //   var index = keys.length;
    //   if (index < 1) throw new Error('bindAll must be passed function names');
    //   while (index--) {
    //     var key = keys[index];
    //     obj[key] = _.bind(obj[key], obj);
    //   }
    // });
  
    // // Memoize an expensive function by storing its results.
    // _.memoize = function(func, hasher) {
    //   var memoize = function(key) {
    //     var cache = memoize.cache;
    //     var address = '' + (hasher ? hasher.apply(this, arguments) : key);
    //     if (!has(cache, address)) cache[address] = func.apply(this, arguments);
    //     return cache[address];
    //   };
    //   memoize.cache = {};
    //   return memoize;
    // };
  
    // // Delays a function for the given number of milliseconds, and then calls
    // // it with the arguments supplied.
    // _.delay = restArguments(function(func, wait, args) {
    //   return setTimeout(function() {
    //     return func.apply(null, args);
    //   }, wait);
    // });
  
    // // Defers a function, scheduling it to run after the current call stack has
    // // cleared.
    // _.defer = _.partial(_.delay, _, 1);
  
    // // Returns a function, that, when invoked, will only be triggered at most once
    // // during a given window of time. Normally, the throttled function will run
    // // as much as it can, without ever going more than once per `wait` duration;
    // // but if you'd like to disable the execution on the leading edge, pass
    // // `{leading: false}`. To disable execution on the trailing edge, ditto.
    // _.throttle = function(func, wait, options) {
    //   var timeout, context, args, result;
    //   var previous = 0;
    //   if (!options) options = {};
  
    //   var later = function() {
    //     previous = options.leading === false ? 0 : _.now();
    //     timeout = null;
    //     result = func.apply(context, args);
    //     if (!timeout) context = args = null;
    //   };
  
    //   var throttled = function() {
    //     var now = _.now();
    //     if (!previous && options.leading === false) previous = now;
    //     var remaining = wait - (now - previous);
    //     context = this;
    //     args = arguments;
    //     if (remaining <= 0 || remaining > wait) {
    //       if (timeout) {
    //         clearTimeout(timeout);
    //         timeout = null;
    //       }
    //       previous = now;
    //       result = func.apply(context, args);
    //       if (!timeout) context = args = null;
    //     } else if (!timeout && options.trailing !== false) {
    //       timeout = setTimeout(later, remaining);
    //     }
    //     return result;
    //   };
  
    //   throttled.cancel = function() {
    //     clearTimeout(timeout);
    //     previous = 0;
    //     timeout = context = args = null;
    //   };
  
    //   return throttled;
    // };
  
    // // Returns a function, that, as long as it continues to be invoked, will not
    // // be triggered. The function will be called after it stops being called for
    // // N milliseconds. If `immediate` is passed, trigger the function on the
    // // leading edge, instead of the trailing.
    // _.debounce = function(func, wait, immediate) {
    //   var timeout, result;
  
    //   var later = function(context, args) {
    //     timeout = null;
    //     if (args) result = func.apply(context, args);
    //   };
  
    //   var debounced = restArguments(function(args) {
    //     if (timeout) clearTimeout(timeout);
    //     if (immediate) {
    //       var callNow = !timeout;
    //       timeout = setTimeout(later, wait);
    //       if (callNow) result = func.apply(this, args);
    //     } else {
    //       timeout = _.delay(later, wait, this, args);
    //     }
  
    //     return result;
    //   });
  
    //   debounced.cancel = function() {
    //     clearTimeout(timeout);
    //     timeout = null;
    //   };
  
    //   return debounced;
    // };
  
    // // Returns the first function passed as an argument to the second,
    // // allowing you to adjust arguments, run code before and after, and
    // // conditionally execute the original function.
    // _.wrap = function(func, wrapper) {
    //   return _.partial(wrapper, func);
    // };
  
    // // Returns a negated version of the passed-in predicate.
    // _.negate = function(predicate) {
    //   return function() {
    //     return !predicate.apply(this, arguments);
    //   };
    // };
  
    // // Returns a function that is the composition of a list of functions, each
    // // consuming the return value of the function that follows.
    // _.compose = function() {
    //   var args = arguments;
    //   var start = args.length - 1;
    //   return function() {
    //     var i = start;
    //     var result = args[start].apply(this, arguments);
    //     while (i--) result = args[i].call(this, result);
    //     return result;
    //   };
    // };
  
    // // Returns a function that will only be executed on and after the Nth call.
    // _.after = function(times, func) {
    //   return function() {
    //     if (--times < 1) {
    //       return func.apply(this, arguments);
    //     }
    //   };
    // };
  
    // // Returns a function that will only be executed up to (but not including) the Nth call.
    // _.before = function(times, func) {
    //   var memo;
    //   return function() {
    //     if (--times > 0) {
    //       memo = func.apply(this, arguments);
    //     }
    //     if (times <= 1) func = null;
    //     return memo;
    //   };
    // };
  
    // // Returns a function that will be executed at most one time, no matter how
    // // often you call it. Useful for lazy initialization.
    // _.once = _.partial(_.before, 2);
  
    // _.restArguments = restArguments;
  
    // // Object Functions
    // // ----------------
  
    // // Keys in IE < 9 that won't be iterated by `for key in ...` and thus missed.
    // var hasEnumBug = !{toString: null}.propertyIsEnumerable('toString');
    // var nonEnumerableProps = ['valueOf', 'isPrototypeOf', 'toString',
    //   'propertyIsEnumerable', 'hasOwnProperty', 'toLocaleString'];
  
    // var collectNonEnumProps = function(obj, keys) {
    //   var nonEnumIdx = nonEnumerableProps.length;
    //   var constructor = obj.constructor;
    //   var proto = _.isFunction(constructor) && constructor.prototype || ObjProto;
  
    //   // Constructor is a special case.
    //   var prop = 'constructor';
    //   if (has(obj, prop) && !_.contains(keys, prop)) keys.push(prop);
  
    //   while (nonEnumIdx--) {
    //     prop = nonEnumerableProps[nonEnumIdx];
    //     if (prop in obj && obj[prop] !== proto[prop] && !_.contains(keys, prop)) {
    //       keys.push(prop);
    //     }
    //   }
    // };
  
    // // Retrieve the names of an object's own properties.
    // // Delegates to **ECMAScript 5**'s native `Object.keys`.
    // _.keys = function(obj) {
    //   if (!_.isObject(obj)) return [];
    //   if (nativeKeys) return nativeKeys(obj);
    //   var keys = [];
    //   for (var key in obj) if (has(obj, key)) keys.push(key);
    //   // Ahem, IE < 9.
    //   if (hasEnumBug) collectNonEnumProps(obj, keys);
    //   return keys;
    // };
  
    // // Retrieve all the property names of an object.
    // _.allKeys = function(obj) {
    //   if (!_.isObject(obj)) return [];
    //   var keys = [];
    //   for (var key in obj) keys.push(key);
    //   // Ahem, IE < 9.
    //   if (hasEnumBug) collectNonEnumProps(obj, keys);
    //   return keys;
    // };
  
    // // Retrieve the values of an object's properties.
    // _.values = function(obj) {
    //   var keys = _.keys(obj);
    //   var length = keys.length;
    //   var values = Array(length);
    //   for (var i = 0; i < length; i++) {
    //     values[i] = obj[keys[i]];
    //   }
    //   return values;
    // };
  
    // // Returns the results of applying the iteratee to each element of the object.
    // // In contrast to _.map it returns an object.
    // _.mapObject = function(obj, iteratee, context) {
    //   iteratee = cb(iteratee, context);
    //   var keys = _.keys(obj),
    //       length = keys.length,
    //       results = {};
    //   for (var index = 0; index < length; index++) {
    //     var currentKey = keys[index];
    //     results[currentKey] = iteratee(obj[currentKey], currentKey, obj);
    //   }
    //   return results;
    // };
  
    // // Convert an object into a list of `[key, value]` pairs.
    // // The opposite of _.object.
    // _.pairs = function(obj) {
    //   var keys = _.keys(obj);
    //   var length = keys.length;
    //   var pairs = Array(length);
    //   for (var i = 0; i < length; i++) {
    //     pairs[i] = [keys[i], obj[keys[i]]];
    //   }
    //   return pairs;
    // };
  
    // // Invert the keys and values of an object. The values must be serializable.
    // _.invert = function(obj) {
    //   var result = {};
    //   var keys = _.keys(obj);
    //   for (var i = 0, length = keys.length; i < length; i++) {
    //     result[obj[keys[i]]] = keys[i];
    //   }
    //   return result;
    // };
  
    // Return a sorted list of the function names available on the object.
    // Aliased as `methods`.
    // _.functions = _.methods = function(obj) {
    //   var names = [];
    //   for (var key in obj) {
    //     if (_.isFunction(obj[key])) names.push(key);
    //   }
    //   return names.sort();
    // };
  
    // // An internal function for creating assigner functions.
    // var createAssigner = function(keysFunc, defaults) {
    //   return function(obj) {
    //     var length = arguments.length;
    //     if (defaults) obj = Object(obj);
    //     if (length < 2 || obj == null) return obj;
    //     for (var index = 1; index < length; index++) {
    //       var source = arguments[index],
    //           keys = keysFunc(source),
    //           l = keys.length;
    //       for (var i = 0; i < l; i++) {
    //         var key = keys[i];
    //         if (!defaults || obj[key] === void 0) obj[key] = source[key];
    //       }
    //     }
    //     return obj;
    //   };
    // };
  
    // // Extend a given object with all the properties in passed-in object(s).
    // _.extend = createAssigner(_.allKeys);
  
    // // Assigns a given object with all the own properties in the passed-in object(s).
    // // (https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/assign)
    // _.extendOwn = _.assign = createAssigner(_.keys);
  
    // // Returns the first key on an object that passes a predicate test.
    // _.findKey = function(obj, predicate, context) {
    //   predicate = cb(predicate, context);
    //   var keys = _.keys(obj), key;
    //   for (var i = 0, length = keys.length; i < length; i++) {
    //     key = keys[i];
    //     if (predicate(obj[key], key, obj)) return key;
    //   }
    // };
  
    // // Internal pick helper function to determine if `obj` has key `key`.
    // var keyInObj = function(value, key, obj) {
    //   return key in obj;
    // };
  
    // // Return a copy of the object only containing the whitelisted properties.
    // _.pick = restArguments(function(obj, keys) {
    //   var result = {}, iteratee = keys[0];
    //   if (obj == null) return result;
    //   if (_.isFunction(iteratee)) {
    //     if (keys.length > 1) iteratee = optimizeCb(iteratee, keys[1]);
    //     keys = _.allKeys(obj);
    //   } else {
    //     iteratee = keyInObj;
    //     keys = flatten(keys, false, false);
    //     obj = Object(obj);
    //   }
    //   for (var i = 0, length = keys.length; i < length; i++) {
    //     var key = keys[i];
    //     var value = obj[key];
    //     if (iteratee(value, key, obj)) result[key] = value;
    //   }
    //   return result;
    // });
  
    // // Return a copy of the object without the blacklisted properties.
    // _.omit = restArguments(function(obj, keys) {
    //   var iteratee = keys[0], context;
    //   if (_.isFunction(iteratee)) {
    //     iteratee = _.negate(iteratee);
    //     if (keys.length > 1) context = keys[1];
    //   } else {
    //     keys = _.map(flatten(keys, false, false), String);
    //     iteratee = function(value, key) {
    //       return !_.contains(keys, key);
    //     };
    //   }
    //   return _.pick(obj, iteratee, context);
    // });
  
    // // Fill in a given object with default properties.
    // _.defaults = createAssigner(_.allKeys, true);
  
    // // Creates an object that inherits from the given prototype object.
    // // If additional properties are provided then they will be added to the
    // // created object.
    // _.create = function(prototype, props) {
    //   var result = baseCreate(prototype);
    //   if (props) _.extendOwn(result, props);
    //   return result;
    // };
  
    // // Create a (shallow-cloned) duplicate of an object.
    // _.clone = function(obj) {
    //   if (!_.isObject(obj)) return obj;
    //   return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
    // };
  
    // // Invokes interceptor with the obj, and then returns obj.
    // // The primary purpose of this method is to "tap into" a method chain, in
    // // order to perform operations on intermediate results within the chain.
    // _.tap = function(obj, interceptor) {
    //   interceptor(obj);
    //   return obj;
    // };
  
    // // Returns whether an object has a given set of `key:value` pairs.
    // _.isMatch = function(object, attrs) {
    //   var keys = _.keys(attrs), length = keys.length;
    //   if (object == null) return !length;
    //   var obj = Object(object);
    //   for (var i = 0; i < length; i++) {
    //     var key = keys[i];
    //     if (attrs[key] !== obj[key] || !(key in obj)) return false;
    //   }
    //   return true;
    // };
  
  
    // // Internal recursive comparison function for `isEqual`.
    // var eq, deepEq;
    // eq = function(a, b, aStack, bStack) {
    //   // Identical objects are equal. `0 === -0`, but they aren't identical.
    //   // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
    //   if (a === b) return a !== 0 || 1 / a === 1 / b;
    //   // `null` or `undefined` only equal to itself (strict comparison).
    //   if (a == null || b == null) return false;
    //   // `NaN`s are equivalent, but non-reflexive.
    //   if (a !== a) return b !== b;
    //   // Exhaust primitive checks
    //   var type = typeof a;
    //   if (type !== 'function' && type !== 'object' && typeof b != 'object') return false;
    //   return deepEq(a, b, aStack, bStack);
    // };
  
    // // Internal recursive comparison function for `isEqual`.
    // deepEq = function(a, b, aStack, bStack) {
    //   // Unwrap any wrapped objects.
    //   if (a instanceof _) a = a._wrapped;
    //   if (b instanceof _) b = b._wrapped;
    //   // Compare `[[Class]]` names.
    //   var className = toString.call(a);
    //   if (className !== toString.call(b)) return false;
    //   switch (className) {
    //     // Strings, numbers, regular expressions, dates, and booleans are compared by value.
    //     case '[object RegExp]':
    //     // RegExps are coerced to strings for comparison (Note: '' + /a/i === '/a/i')
    //     case '[object String]':
    //       // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
    //       // equivalent to `new String("5")`.
    //       return '' + a === '' + b;
    //     case '[object Number]':
    //       // `NaN`s are equivalent, but non-reflexive.
    //       // Object(NaN) is equivalent to NaN.
    //       if (+a !== +a) return +b !== +b;
    //       // An `egal` comparison is performed for other numeric values.
    //       return +a === 0 ? 1 / +a === 1 / b : +a === +b;
    //     case '[object Date]':
    //     case '[object Boolean]':
    //       // Coerce dates and booleans to numeric primitive values. Dates are compared by their
    //       // millisecond representations. Note that invalid dates with millisecond representations
    //       // of `NaN` are not equivalent.
    //       return +a === +b;
    //     case '[object Symbol]':
    //       return SymbolProto.valueOf.call(a) === SymbolProto.valueOf.call(b);
    //   }
  
    //   var areArrays = className === '[object Array]';
    //   if (!areArrays) {
    //     if (typeof a != 'object' || typeof b != 'object') return false;
  
    //     // Objects with different constructors are not equivalent, but `Object`s or `Array`s
    //     // from different frames are.
    //     var aCtor = a.constructor, bCtor = b.constructor;
    //     if (aCtor !== bCtor && !(_.isFunction(aCtor) && aCtor instanceof aCtor &&
    //                              _.isFunction(bCtor) && bCtor instanceof bCtor)
    //                         && ('constructor' in a && 'constructor' in b)) {
    //       return false;
    //     }
    //   }
    //   // Assume equality for cyclic structures. The algorithm for detecting cyclic
    //   // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
  
    //   // Initializing stack of traversed objects.
    //   // It's done here since we only need them for objects and arrays comparison.
    //   aStack = aStack || [];
    //   bStack = bStack || [];
    //   var length = aStack.length;
    //   while (length--) {
    //     // Linear search. Performance is inversely proportional to the number of
    //     // unique nested structures.
    //     if (aStack[length] === a) return bStack[length] === b;
    //   }
  
    //   // Add the first object to the stack of traversed objects.
    //   aStack.push(a);
    //   bStack.push(b);
  
    //   // Recursively compare objects and arrays.
    //   if (areArrays) {
    //     // Compare array lengths to determine if a deep comparison is necessary.
    //     length = a.length;
    //     if (length !== b.length) return false;
    //     // Deep compare the contents, ignoring non-numeric properties.
    //     while (length--) {
    //       if (!eq(a[length], b[length], aStack, bStack)) return false;
    //     }
    //   } else {
    //     // Deep compare objects.
    //     var keys = _.keys(a), key;
    //     length = keys.length;
    //     // Ensure that both objects contain the same number of properties before comparing deep equality.
    //     if (_.keys(b).length !== length) return false;
    //     while (length--) {
    //       // Deep compare each member
    //       key = keys[length];
    //       if (!(has(b, key) && eq(a[key], b[key], aStack, bStack))) return false;
    //     }
    //   }
    //   // Remove the first object from the stack of traversed objects.
    //   aStack.pop();
    //   bStack.pop();
    //   return true;
    // };
  
    // // Perform a deep comparison to check if two objects are equal.
    // _.isEqual = function(a, b) {
    //   return eq(a, b);
    // };
  
    // // Is a given array, string, or object empty?
    // // An "empty" object has no enumerable own-properties.
    // _.isEmpty = function(obj) {
    //   if (obj == null) return true;
    //   if (isArrayLike(obj) && (_.isArray(obj) || _.isString(obj) || _.isArguments(obj))) return obj.length === 0;
    //   return _.keys(obj).length === 0;
    // };
  
    // // Is a given value a DOM element?
    // _.isElement = function(obj) {
    //   return !!(obj && obj.nodeType === 1);
    // };
  
    // // Is a given value an array?
    // // Delegates to ECMA5's native Array.isArray
    // _.isArray = nativeIsArray || function(obj) {
    //   return toString.call(obj) === '[object Array]';
    // };
  
    // // Is a given variable an object?
    // _.isObject = function(obj) {
    //   var type = typeof obj;
    //   return type === 'function' || type === 'object' && !!obj;
    // };
  
    // // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp, isError, isMap, isWeakMap, isSet, isWeakSet.
    // _.each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp', 'Error', 'Symbol', 'Map', 'WeakMap', 'Set', 'WeakSet'], function(name) {
    //   _['is' + name] = function(obj) {
    //     return toString.call(obj) === '[object ' + name + ']';
    //   };
    // });
  
    // // Define a fallback version of the method in browsers (ahem, IE < 9), where
    // // there isn't any inspectable "Arguments" type.
    // if (!_.isArguments(arguments)) {
    //   _.isArguments = function(obj) {
    //     return has(obj, 'callee');
    //   };
    // }
  
    // // Optimize `isFunction` if appropriate. Work around some typeof bugs in old v8,
    // // IE 11 (#1621), Safari 8 (#1929), and PhantomJS (#2236).
    // var nodelist = root.document && root.document.childNodes;
    // if (typeof /./ != 'function' && typeof Int8Array != 'object' && typeof nodelist != 'function') {
    //   _.isFunction = function(obj) {
    //     return typeof obj == 'function' || false;
    //   };
    // }
  
    // // Is a given object a finite number?
    // _.isFinite = function(obj) {
    //   return !_.isSymbol(obj) && isFinite(obj) && !isNaN(parseFloat(obj));
    // };
  
    // // Is the given value `NaN`?
    // _.isNaN = function(obj) {
    //   return _.isNumber(obj) && isNaN(obj);
    // };
  
    // // Is a given value a boolean?
    // _.isBoolean = function(obj) {
    //   return obj === true || obj === false || toString.call(obj) === '[object Boolean]';
    // };
  
    // // Is a given value equal to null?
    // _.isNull = function(obj) {
    //   return obj === null;
    // };
  
    // // Is a given variable undefined?
    // _.isUndefined = function(obj) {
    //   return obj === void 0;
    // };
  
    // // Shortcut function for checking if an object has a given property directly
    // // on itself (in other words, not on a prototype).
    // _.has = function(obj, path) {
    //   if (!_.isArray(path)) {
    //     return has(obj, path);
    //   }
    //   var length = path.length;
    //   for (var i = 0; i < length; i++) {
    //     var key = path[i];
    //     if (obj == null || !hasOwnProperty.call(obj, key)) {
    //       return false;
    //     }
    //     obj = obj[key];
    //   }
    //   return !!length;
    // };
  
    // // Utility Functions
    // // -----------------
  
    // // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
    // // previous owner. Returns a reference to the Underscore object.
    // _.noConflict = function() {
    //   root._ = previousUnderscore;
    //   return this;
    // };
  
    // // Keep the identity function around for default iteratees.
    // _.identity = function(value) {
    //   return value;
    // };
  
    // // Predicate-generating functions. Often useful outside of Underscore.
    // _.constant = function(value) {
    //   return function() {
    //     return value;
    //   };
    // };
  
    // _.noop = function(){};
  
    // // Creates a function that, when passed an object, will traverse that object’s
    // // properties down the given `path`, specified as an array of keys or indexes.
    // _.property = function(path) {
    //   if (!_.isArray(path)) {
    //     return shallowProperty(path);
    //   }
    //   return function(obj) {
    //     return deepGet(obj, path);
    //   };
    // };
  
    // // Generates a function for a given object that returns a given property.
    // _.propertyOf = function(obj) {
    //   if (obj == null) {
    //     return function(){};
    //   }
    //   return function(path) {
    //     return !_.isArray(path) ? obj[path] : deepGet(obj, path);
    //   };
    // };
  
    // // Returns a predicate for checking whether an object has a given set of
    // // `key:value` pairs.
    // _.matcher = _.matches = function(attrs) {
    //   attrs = _.extendOwn({}, attrs);
    //   return function(obj) {
    //     return _.isMatch(obj, attrs);
    //   };
    // };
  
    // // Run a function **n** times.
    // _.times = function(n, iteratee, context) {
    //   var accum = Array(Math.max(0, n));
    //   iteratee = optimizeCb(iteratee, context, 1);
    //   for (var i = 0; i < n; i++) accum[i] = iteratee(i);
    //   return accum;
    // };
  
    // // Return a random integer between min and max (inclusive).
    // _.random = function(min, max) {
    //   if (max == null) {
    //     max = min;
    //     min = 0;
    //   }
    //   return min + Math.floor(Math.random() * (max - min + 1));
    // };
  
    // // A (possibly faster) way to get the current timestamp as an integer.
    // _.now = Date.now || function() {
    //   return new Date().getTime();
    // };
  
    // // List of HTML entities for escaping.
    // var escapeMap = {
    //   '&': '&amp;',
    //   '<': '&lt;',
    //   '>': '&gt;',
    //   '"': '&quot;',
    //   "'": '&#x27;',
    //   '`': '&#x60;'
    // };
    // var unescapeMap = _.invert(escapeMap);
  
    // // Functions for escaping and unescaping strings to/from HTML interpolation.
    // var createEscaper = function(map) {
    //   var escaper = function(match) {
    //     return map[match];
    //   };
    //   // Regexes for identifying a key that needs to be escaped.
    //   var source = '(?:' + _.keys(map).join('|') + ')';
    //   var testRegexp = RegExp(source);
    //   var replaceRegexp = RegExp(source, 'g');
    //   return function(string) {
    //     string = string == null ? '' : '' + string;
    //     return testRegexp.test(string) ? string.replace(replaceRegexp, escaper) : string;
    //   };
    // };
    // _.escape = createEscaper(escapeMap);
    // _.unescape = createEscaper(unescapeMap);
  
    // // Traverses the children of `obj` along `path`. If a child is a function, it
    // // is invoked with its parent as context. Returns the value of the final
    // // child, or `fallback` if any child is undefined.
    // _.result = function(obj, path, fallback) {
    //   if (!_.isArray(path)) path = [path];
    //   var length = path.length;
    //   if (!length) {
    //     return _.isFunction(fallback) ? fallback.call(obj) : fallback;
    //   }
    //   for (var i = 0; i < length; i++) {
    //     var prop = obj == null ? void 0 : obj[path[i]];
    //     if (prop === void 0) {
    //       prop = fallback;
    //       i = length; // Ensure we don't continue iterating.
    //     }
    //     obj = _.isFunction(prop) ? prop.call(obj) : prop;
    //   }
    //   return obj;
    // };
  
    // // Generate a unique integer id (unique within the entire client session).
    // // Useful for temporary DOM ids.
    // var idCounter = 0;
    // _.uniqueId = function(prefix) {
    //   var id = ++idCounter + '';
    //   return prefix ? prefix + id : id;
    // };
  
    // // By default, Underscore uses ERB-style template delimiters, change the
    // // following template settings to use alternative delimiters.
    // _.templateSettings = {
    //   evaluate: /<%([\s\S]+?)%>/g,
    //   interpolate: /<%=([\s\S]+?)%>/g,
    //   escape: /<%-([\s\S]+?)%>/g
    // };
  
    // // When customizing `templateSettings`, if you don't want to define an
    // // interpolation, evaluation or escaping regex, we need one that is
    // // guaranteed not to match.
    // var noMatch = /(.)^/;
  
    // // Certain characters need to be escaped so that they can be put into a
    // // string literal.
    // var escapes = {
    //   "'": "'",
    //   '\\': '\\',
    //   '\r': 'r',
    //   '\n': 'n',
    //   '\u2028': 'u2028',
    //   '\u2029': 'u2029'
    // };
  
    // var escapeRegExp = /\\|'|\r|\n|\u2028|\u2029/g;
  
    // var escapeChar = function(match) {
    //   return '\\' + escapes[match];
    // };
  
    // // JavaScript micro-templating, similar to John Resig's implementation.
    // // Underscore templating handles arbitrary delimiters, preserves whitespace,
    // // and correctly escapes quotes within interpolated code.
    // // NB: `oldSettings` only exists for backwards compatibility.
    // _.template = function(text, settings, oldSettings) {
    //   if (!settings && oldSettings) settings = oldSettings;
    //   settings = _.defaults({}, settings, _.templateSettings);
  
    //   // Combine delimiters into one regular expression via alternation.
    //   var matcher = RegExp([
    //     (settings.escape || noMatch).source,
    //     (settings.interpolate || noMatch).source,
    //     (settings.evaluate || noMatch).source
    //   ].join('|') + '|$', 'g');
  
    //   // Compile the template source, escaping string literals appropriately.
    //   var index = 0;
    //   var source = "__p+='";
    //   text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
    //     source += text.slice(index, offset).replace(escapeRegExp, escapeChar);
    //     index = offset + match.length;
  
    //     if (escape) {
    //       source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
    //     } else if (interpolate) {
    //       source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
    //     } else if (evaluate) {
    //       source += "';\n" + evaluate + "\n__p+='";
    //     }
  
    //     // Adobe VMs need the match returned to produce the correct offset.
    //     return match;
    //   });
    //   source += "';\n";
  
    //   // If a variable is not specified, place data values in local scope.
    //   if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
  
    //   source = "var __t,__p='',__j=Array.prototype.join," +
    //     "print=function(){__p+=__j.call(arguments,'');};\n" +
    //     source + 'return __p;\n';
  
    //   var render;
    //   try {
    //     render = new Function(settings.variable || 'obj', '_', source);
    //   } catch (e) {
    //     e.source = source;
    //     throw e;
    //   }
  
    //   var template = function(data) {
    //     return render.call(this, data, _);
    //   };
  
    //   // Provide the compiled source as a convenience for precompilation.
    //   var argument = settings.variable || 'obj';
    //   template.source = 'function(' + argument + '){\n' + source + '}';
  
    //   return template;
    // };
  
    // // Add a "chain" function. Start chaining a wrapped Underscore object.
    // _.chain = function(obj) {
    //   var instance = _(obj);
    //   instance._chain = true;
    //   return instance;
    // };
  
    // // OOP
    // // ---------------
    // // If Underscore is called as a function, it returns a wrapped object that
    // // can be used OO-style. This wrapper holds altered versions of all the
    // // underscore functions. Wrapped objects may be chained.
  
    // // Helper function to continue chaining intermediate results.
    // var chainResult = function(instance, obj) {
    //   return instance._chain ? _(obj).chain() : obj;
    // };
  
    // // Add your own custom functions to the Underscore object.
    // _.mixin = function(obj) {
    //   _.each(_.functions(obj), function(name) {
    //     var func = _[name] = obj[name];
    //     _.prototype[name] = function() {
    //       var args = [this._wrapped];
    //       push.apply(args, arguments);
    //       return chainResult(this, func.apply(_, args));
    //     };
    //   });
    //   return _;
    // };
  
    // // Add all of the Underscore functions to the wrapper object.
    // _.mixin(_);
  
    // // Add all mutator Array functions to the wrapper.
    // _.each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
    //   var method = ArrayProto[name];
    //   _.prototype[name] = function() {
    //     var obj = this._wrapped;
    //     method.apply(obj, arguments);
    //     if ((name === 'shift' || name === 'splice') && obj.length === 0) delete obj[0];
    //     return chainResult(this, obj);
    //   };
    // });
  
    // // Add all accessor Array functions to the wrapper.
    // _.each(['concat', 'join', 'slice'], function(name) {
    //   var method = ArrayProto[name];
    //   _.prototype[name] = function() {
    //     return chainResult(this, method.apply(this._wrapped, arguments));
    //   };
    // });
  
    // // Extracts the result from a wrapped and chained object.
    // _.prototype.value = function() {
    //   return this._wrapped;
    // };
  
    // // Provide unwrapping proxy for some methods used in engine operations
    // // such as arithmetic and JSON stringification.
    // _.prototype.valueOf = _.prototype.toJSON = _.prototype.value;
  
    // _.prototype.toString = function() {
    //   return String(this._wrapped);
    // };
    _.hello = function(obj){
      console.log('hello,' + obj)
    }
  
    // AMD registration happens at the end for compatibility with AMD loaders
    // that may not enforce next-turn semantics on modules. Even though general
    // practice for AMD registration is to be anonymous, underscore registers
    // as a named module because, like jQuery, it is a base library that is
    // popular enough to be bundled in a third party lib, but not be part of
    // an AMD load request. Those cases could generate an error when an
    // anonymous define() is called outside of a loader request.
    // if (typeof define == 'function' && define.amd) {
    //   define('underscore', [], function() {
    //     return _;
    //   });
    // }
  }());